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Above Average Precipitation in 2017 for Contiguous USA


2017 was the 19th wettest year on record across the contiguous USA.


Figure 1. Source: NOAA, Climate-at-a-Glance.

So says data from Climate-At-A-Glance, the data portal operated by the National Oceanographic and Atmospheric Administration (NOAA). Figure 1 shows the data, with the green line representing actual yearly precipitation, and the blue line representing the trend across time. The left vertical scale shows inches of precipitation, while the right shows millimeters of precipitation. In 2017, the average precipitation across the contiguous USA was 32.21 inches, which was the 19th highest amount in the record. Over time, precipitation seems to be increasing at about 0.17 inches per decade. The trend towards more precipitation is present in the Eastern Climate Region (+0.25 inches per decade), the Southern Climate Region (+0.22 inches per decade), and the Central Climate Region (+0.22 inches per decade). It is almost absent in the Western Climate Region, however (+0.03 inches per decade). (Except where noted, data is from the Climate-at-a-Glance data portal.)

(Click on figure for larger view.)

Figure 2. Source: NOAA, Climate-at-a-Glance.

In Missouri, 2017 was the 51st wettest year on record, with 41.22 inches of precipitation. (Figure 2) This puts the year slightly above the long-term average. As expected, the variation from year-to-year is much larger than the change in precipitation over time, but since 1895 Missouri has trended towards about 0.24 inches more precipitation per decade.

The interesting thing about Missouri’s precipitation is that in each of the last 2 years, concentrated storm systems have moved across the state from southwest to northeast, roughly following the route of I-44. They have led to huge amounts of rain over periods of a couple of days, resulting in damaging flooding. (See here and here.) This pattern is the one predicted by climate change models – slightly increased precipitation occurring in heavy precipitation events, with longer, drier spells between. (Drier because increased temperatures will cause the soil to dry out more quickly.)

Table 3. Source: NOAA, Climate-at-a-Glance.

The Northern Rockies and Plains are where most of the water that flows into the Missouri River originates, and the Missouri River provides water to more Missourians than any other source. This region saw 21.17 inches of precipitation in 2017, some 0.28 inches below average. (Figure 3) As expected, the variation between years is much larger than the change over time, but here, too, precipitation has been increasing, though the change has only been +0.07 inches per decade.

What to watch for in Missouri, then, does not appear to be a decrease in average yearly precipitation, but two other issues. First, demand for water has been increasing. Will it grow to outstrip the supply? Second, climate change is causing precipitation that once fell as snow to fall as rain. This changes the timing of when the Missouri River receives the runoff. Will that affect the ability of the river to supply water to meet the demand for water? So far, these answers are not known. (For a more extended discussion, see here.)

Figure 4. Source: NOAA, Climate-at-a-Glance.

The water situation in California is more serious than it is in the Northern Rockies and Plains, Missouri, or contiguous USA. California has a monsoonal precipitation pattern, and it has regions that receive a great deal of precipitation, while other regions receive little, if any. Consequently, the state relies on snowfall during the winter, which runs off during the spring and early summer, and is collected into reservoirs. This water is then distributed around the state. Thus, the amount of water contained in the snowpack on April 1, which is when it historically started melting in earnest, has been seen to be crucial to California’s water status.

After a severe, multi-year drought, last year was a big water year in California. (Figure 4) They received huge amounts of snow during January and February. For instance, the Mammoth Mountain Ski Area received 408 inches of snow during the 2 months. (Mammoth Mountain 2018) Over the whole year California received 27.63 inches of precipitation. That is the 22nd highest amount in the record, and it is 5.24 inches more than average.

Figure 5. Source: California Data Exchange Center, Dept. of Water Resources.

Unfortunately, this winter is not being as kind to California as last year, at least not so far. December, 2017, was the 2nd driest December on record, with only 1989 being dryer. The snowpack measurements suggest that the state has only about 22% of the snowpack that is average for this time of year (Figure 5, data as of 1/22/2018, California Snowpack Survey 2018) This is echoed by data from the Mammoth Mountain Ski Area, which reports only 73 inches of snow to date, vs. 349.5 inches through the end of January last year. (As I write, there are a few days left in January, but it still looks like a very serious shortfall to me.)

The snowpack is also below average in the Colorado River Basin above Lake Powell, the other major source for California’s water. As of 1/28/2018, the snowpack is only 65% of the average for this date. (National Resource Conservation Service, 1/28/2018) Now, snow tends to fall during storms, and there is no predicting when the storms will come. February and March could still bring much-needed snow. But California just got out of a terrible multi-year drought, and it would be very disappointing if it went right back into another after only 1 year.

ADDENDUM: A few days after I wrote this article, the New York Times published one on the water crisis in Cape Town, South Africa. That city is only about 3 months from running completely out of water. This blog focuses on statistics and big pictures. If you want a perspective on what such a crisis might actually look like in an urban area, I recommend the Times article.

Sources:

California Data Exchange Center, Department of Water Resources. Current Year Regional Snow Sensor Water Content Chart (PDF). Downloaded 1/22/2018 from https://cdec.water.ca.gov/water_cond.html.

Mammoth Mountain Ski Area. 2018. Snow Conditions and Weather: Snow History. Viewed online 1/15/2018 at NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, published January 2018, retrieved on January 15, 2018 from http://www.ncdc.noaa.gov/cag.

Natural Resource Conservation Service, U.S. Department of Agriculture. Upper Colorado River Basin SNOTEL Snowpack Update Report. Viewed online 1/28/2018 at https://wcc.sc.egov.usda.gov/reports/UpdateReport.html?textReport.

NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, published January 2018, retrieved on January 15, 2018 from http://www.ncdc.noaa.gov/cag.

The Second Warmest Year Ever


2017 was the 2nd warmest year on record globally, and the 3rd warmest for the contiguous USA.


Figure 1. Data source: NOAA, Climate-at-a-Glance.

Figure 1 shows the average annual temperature for the Earth from 1880-2017. The chart shows the temperature as an anomaly. That means that they calculated the mean annual temperature for the whole series, and then presented the data as a deviation from that mean. Degrees Celsius are on the left vertical axis, and degrees Fahrenheit are on the right. Because the earth contains very hot regions near the equator and very cold polar regions, the actual mean temperature has relatively little meaning, and Climate-at-a Glance does not include it in their chart. (Except where noted, all data is from NOAA, Climate at a Glance.) 2016 was the highest on record, but 2017 was second. The 4 highest readings have all occurred within the last 4 years. You can see that the Earth appears to have been in a cooling trend until around 1910, then a warming trend until mid-Century, then a cooling period until the late 1960s or early 1970s, and then a warming period since 1970. Over the whole series, the warming trend has been 0.07°C per decade, which equals 0.13°F per decade. Since 1970, however, the warming has accelerated to 0.18°C per decade (0.32°F).

(Click on chart for larger view.)

Figure 2. Data source: NOAA, Climate-at-a-Glance.

Figure 2 shows the average yearly temperature for the contiguous United States from 1895 to 2017. In this chart and those that follow, the vertical axes are reversed, with °F on the left vertical axis, and °C on the right. The purple line shows the data, and the blue line shows the trend. 2017 was the 3rd highest in the record at 54.58°F. The 4 highest readings have all come within the last 6 years. Over time, the average temperature has increased 0.15°F per decade. Since 1970, however, the rate has increased to 0.52°F per decade.

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Figure 3. Data source: NOAA, Climate-at-a-Glance.

Figure 3 shows the average temperature across Missouri for 2017. Across the state, it was the 8th warmest year on record, with an average temperature of 57.1°F. In Missouri, the warming trend from 1930-1950 was more moderate than it was nationally, and the trend has been for a 0.1°F increase in temperature each decade. Since 1970, however, the increase has accelerated to 0.4°F per decade.

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Figure 4. Data source: NOAA, Climate-at-a-Glance.

Because conditions in the Northern Rockies and Plains affect how much water flows into the Missouri River, which provides more of Missouri’s water supply than any other source, I have also tracked climate statistics for that region. Figure 4 shows the data. Last year was the 11th warmest in the record at 44.9°F. This region has been warming at a rate of 0.2°F per decade over the whole period, but since 1970, the rate has accelerated to 0.5°F per decade.

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Figure 5. Data source: NOAA, Climate-at-a-Glance.

Because I have been concerned about the water supply in California, I also track the climate statistics for that state. Figure 5 shows the data. Last year was the third warmest year in the record, with an average temperature of 60.3°F. California has been warming at a rate of 0.2°F each decade. Since 1970 the rate of increase has accelerated to 0.5°F per decade.

In all 4 locations the average yearly temperature seems to have increased significantly for several decades, then paused during mid-Century, and then resumed climbing, but at an accelerated rate. There seems to be little doubt that across the country it is warmer than it was. In Missouri, the average yearly temperature has been increasing, but at a rate that is somewhat less than in the other locations I looked at.

Sources:

NOAA National Centers for Environmental information, Climate at a Glance: U.S. Time Series, published January 2018, retrieved on January 15, 2018 from http://www.ncdc.noaa.gov/cag.

Did Missouri Have Record Cold?

We’ve had some cold weather in Missouri recently. St. Louis hit -6°F on New Years Day, while Kansas City hit -11°F. But these are not records. The record low on New Years day is -10°F in St. Louis, and -13°F in Kansas City.

Kansas City’s all-time record low is -23°F, which occurred in December 1989.

Figure 1. Data source: National Weather Service, St. Louis Forecast Offices, Personal communication from Spencer Mell.

Figure 1 shows a chart for each winter (December, January, and February). Blue columns are the number of days with a low temperature at or below 0°F in St. Louis, and they run from 1874 to 2016. Red columns are for Kansas City, and they run from 1888 to 2016. The dashed blue line represents the trend over time for St. Louis, the dashed red line for Kansas City. You can see that the number of days varies widely from year-to-year. Many years have 1 day, or even none. In St. Louis the maximum number of days was 18, and it occurred in the winter that began in December 1935. In Kansas City, the maximum number of days was 19, and it occurred twice: in 1935 and 1978.

The trend lines show that in Kansas City, the number of days has not been changing over time. In St. Louis, however, the number of days has decreased over time.

(Click on figure for larger view.)

Figure 2. Data source: National Weather Service, St. Louis Forecast Offices, Personal communication from Spencer Mell.

One can count the number of winters that had 0 days below 0°F, the number of winters that had 1 day, the number of winters that had 2 days, etc. You can then construct a frequency chart of how many years had each number of days. Figure 2 shows such a frequency chart for St. Louis and Kansas City. There have been 54 winters in St. Louis when there were no days with lows at or below 0°F, there have been 28 such winters in Kansas City, and no other number is represented in more years than that.

The number of extremely cold days varies widely from year-to-year, but in St. Louis the average number is 3, and in Kansas City it is 4. St. Louis has experienced 2 days below 0°F this winter, and Kansas City has experienced 4 (both as of 1/16). For comparison, St. Louis has had more than 2 days below 0°F some 51 times since 1874. Kansas City has had more than 4 days below 0°F some 31 times since 1888.

The severe cold began this year on the morning of New Years Day. What about last year? Was it a hot one, or not so hot? The next post will review average temperatures for all of 2017.

Sources:

National Weather Service, Kansas City Forecast Office. 2018. WFO Monthly/Daily Climate Data. Data viewed online 1/15/2018 at http://w2.weather.gov/climate/getclimate.php?date=&wfo=eax&sid=MCI&pil=CF6&recent=yes&specdate=2017-12-31+11%3A11%3A11.

National Weather Service, St. Louis Forecast Office. 2018. Ranked Occurrences of Temperature <= 32 and 0 Degrees (1893-Present). Downloaded 1/15/2018 from http://www.weather.gove/lsx/cli_archive. (Actually contains data back to 1874).

Personal communication from Spencer Mell, Climate Focal Point, National Weather Service, Kansas City Forecast Office.

Record Damage from Disasters in 2017

2017 was a record year for disasters, and in contrast to recent years, the disasters were focused on the United States.

Worldwide losses from disasters summed to$330 billion in 2017, of which only $135 billion was insured, according to a report from Munich Re, an international reinsurance company. Only one other year has seen greater losses: 2011, when the Tohoku earthquake in Japan led to the devastating tsunami and the nuclear meltdown at the Fukushima Daiichi Reactor. The 2017 total was almost double the average loss over the previous 10 years, even adjusting for inflation ($170 billion). (Except as noted below, data from Munich Re 2017. This is a press release from an insurance company. I generally regard peer-reviewed scientific studies, and government report to be more reliable sources. However, it will be some time before those sources report on this data. So think of these numbers as preliminary data that may undergo some revision.)

The total number of disasters numbered 710, an increase from the 10-year average of 605. In 2017, approximately 10,000 people lost their lives to disasters, which is considerably lower than the 10-year average of 60,000.

The United States accounted for 50% of the losses, compared to the long-term average of 32%, and taking a wider view, North America accounted for 83% of them. The major disasters striking the USA and North America were weather related in 2017 (in contrast to the Tohoku earthquake, which was not). Think back through the year, and quite a list comes to mind:

  • Hurricane Harvey made landfall in Texas on August 26, and devastated the region. With losses summing to approximately $85 billion, it was the costliest disaster of 2017.
  • On September 5, Hurricane Irma, the strongest hurricane ever in the open Atlantic, began blowing a swath of destruction through the Caribbean before crossing the Florida Keys, then traveling south-to-north up the Florida Peninsula. Insured losses were $32 billion, uninsured losses are not yet known.
  • Hurricane Maria, the second Category 5 hurricane to clobber the Caribbean in 2 weeks, slammed into Dominica on September 18, before totally devastating Puerto Rico. Total losses have not yet been calculated, but as of this writing, almost 3 months later, more than 1/4 of the island of Puerto Rico remains without electricity. (StatusPR 1/8/2018)
  • Terrible wildfires swept across North America in 2017. The National Interagency Fire Center has not yet posted summary statistics for the year. However, InciWeb indicates that the largest were two fires in Oklahoma: the Northwest Oklahoma Complex, at 779,292 acres, and the Starbuck Fire, at 623,000 acres. Eleven other fires consumed over 100,000 acres. Of course, the ones that grabbed the headlines were in California. In October, 250 wildfires ignited across Northern California, burning over 245,000 acres and causing more than $9.4 billion in damage; 44 people were killed and 8,900 structures were destroyed. In December, a new round of fires broke out north of Los Angeles and East of Santa Barbara. More than 230,000 people were forced to evacuate, over 1,300 structures were destroyed, and 307,900 acres were consumed. (Inciweb, Wikipedia, 2018).
  • During the Spring, a series of severe thunderstorms with accompanying tornadoes and hail, caused insured losses of over $1 billion. These included record floods across Southern Missouri, as 8-12 inches of rain fell over 48 hours in some areas. (National Weather Service 2017)
  • In Asia, some 2,700 people lost their lives due to flooding resulting from an extremely severe monsoon season. In some districts, 3/4 of the territory was under water.

The fires that struck California were unprecedented, and yet, the acres burned by the fires in Oklahoma were more than 5 times larger. The devastation wrought by the hurricanes was beyond imagination – whole islands were virtually destroyed.

As reported many times in this blog, weather conditions play a role in hurricanes, wildfires, and flooding. While my reviews have indicated that damage from weather-related disasters is highly variable from year-to-year, there has also been a clear trend toward more damage. While humans play a role by living in harms way, climate change does, too.

The report from Munich Re includes the following statement: “A key point is that some of the catastrophic events…are giving us a foretaste of what is to come. Because even though individual events cannot be directly traced to climate change, our experts expect such extreme weather to occur more often in the future.” (p.2)

More detailed information on disasters and severe weather events in Missouri and the USA will become available later in the year. The next post will look at 2017 summary weather patterns in Missouri and across the USA.

Sources:

InciWeb, Incident Information System. This is the portal for an interagency information management system. Data was viewed online 1/8/2018 at https://inciweb.nwcg.gov.

Munich Re. 2018. Natural Catastrophe Review: Series of Hurricanes Makes 2017 Year of Highest Insured Losses Ever. Press release downloaded 1/5/2018 from https://www.munichre.com/en/media-relations/publications/press-releases/2018/2018-01-04-press-release/index.html.

National Weather Service. 2017. Historic Flooding Event — 28-30 April 2017. Viewed online 1/8/2018 at https://www.weather.gov/sgf/28-30AprilHistoricFloodingEvent.

StatusPR. Website viewed online 1/8/2018 at http://status.pr.

Wikipedia. 2018. 2017 California Fires. Downloaded 1/8/2018 from https://en.wikipedia.org/wiki/2017_California_wildfires.

Missouri Forest Resources Largely Unchanged in 2016

Forest resources in Missouri were unchanged in 2016, after more than 40 years of gradual increase, according to an estimate by the U.S. Forest Service.

The estimate comes from the Missouri Forest Inventory, which is conducted annually. Data were collected from 7,524 individual forested plots across the state. Researchers surveyed how many trees of each species were located within the plot, and measured their height and girth. Researchers then extrapolated from this data to create a estimates for the whole state.

Table 1. Source: Piva et al, 2017.

Table 1 shows the data. In the table, “forest land” means land that is at least 10% covered by trees. “Timberland” means forest land that is capable of producing more than 20 cubic feet per acre per year of industrial wood crops. Compared to 2011, in 2016 the amount of forest land in Missouri decreased by 0.9%, the number of live trees decreased by 3.8%, the aboveground biomass of live trees increased 2.1% and the net volume of live trees increased 2.9%. The area of timberland decreased 1.1%, while on timberland the number of live trees decreased 3.7%, the aboveground biomass of live trees increased 2.0%, and the net volume of live trees increased 2.7%. All of these changes were either within or just outside the margin of error. Thus, while there may be some very slight change between 2011 and 2016, it appears to have been small.

(Click on table for larger view.)

Figure 1. Area of Forest Land and Timberland in Missouri by Year. Source: Piva and Trieman 2016.

At the time of first settlement Missouri had an estimated 31 million acres of forested land. By 1947, the year of the first forest inventory, it had decreased to 15.2 million acres. As shown in Figure 1, the area of both forest land and timberland bottomed in 1972, and over the next 40 years slowly rebounded to 1947 levels.

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Figure 2. Source: Piva et al, 2017.

As shown in Figure 2, the Eastern Ozarks is the most heavily forested area in the state, with the remainder of the Ozarks next most heavily forested.

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Figure 3. Percent of Tree Species on Missouri Forest Land. Source: Piva et al, 2017.

As shown in Figure 3, Missouri’s forest lands are predominantly oak-hickory forests.

The extent of Missouri’s forest land, and the raw amount of forest that it supports is one factor in assessing the health of Missouri’s forests, but there are other factors as well, such as the presence of invasive nuisance species, the land’s ability to support animal and bird life, the presence of toxins, and the health of the trees on the land. I have discussed some of those issues in this blog, and those who are interested can find the relevant posts under the Land and Water menus at the top of the page.

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Source:

Piva, Ronald and Thomas Treiman. 2017. Forests of Missouri, 2016. Resource Update FS-120. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. https://doi.org/10.2737/FS-RU-120.

Say Goodby to Saline Lakes


“Many of the world’s saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health.”


So begins a recent report in Nature Geoscience.

Figure 1. Major Saline Lakes Across the World. Source: Wurtsbaugh et al, 2017.

Saline lakes, also known as salt lakes, are landlocked bodies of water with a concentration of dissolved minerals several times higher than in freshwater lakes, sometimes even higher than in the ocean. The largest in the world is the Caspian Sea, but other well known saline lakes include the Dead Sea and the Great Salt Lake. Two dozen of the world’s most important saline lakes are shown in Figure 1. The larger blue dots indicate those that formerly had a surface area larger than 250 square kilometers (larger than a circular lake about 18 miles across).

Wayne Wurtsbaugh and his associates looked at the volume of water in 6 saline lakes. The sample is loaded towards the United States, but includes two in Central Asia:

  • The Aral Sea (Kazakhstan and Uzbekistan)
  • The Dead Sea (Israel,  Jordan, and Palestine)
  • The Great Salt Lake (Utah, United States)
  • Lake Urmia (Iran)
  • Owens Lake (California, United States)
  • Walker Lake (Nevada, United States)

Figure 2. Percent Decline in Volume of 6 Saline Lakes. Source: Wurtsbaugh et al, 2017.

Figure 2 shows the loss of water in the 6 lakes over time, with some lakes going back to 1875. Every one of them has experienced a dramatic loss.

The Dead Sea has experienced the lowest percentage loss, the reason being that it is a very deep lake (Maximum depth 978 ft.) Despite that fact, the surface of the lake has dropped 28 feet, and it has been divided in two. (Wikipedia 2018b, Wurtsbaugh et al, 2017).

Starting in 1913, the streams that fed Owens Lake in California were diverted to provide water to Los Angeles. (See my post on California’s water supply, here. For movie buffs, this is also the subject of the famous movie Chinatown.) The lake has been almost completely drained, and is now mostly a dry lake (salt flat). (Wikipedia 2018c)

Figure 2. The Aral Sea in 2014. Source: NASA 2014.

Perhaps the “poster child” for what can happen to dry lakes is the Aral Sea. Formerly one of the largest lakes in the world, with a surface area of 26,300 square miles (almost the size of Lake Superior), water diversion has turned it into several small lakes, plus a whole lot of dry lake bed (salt flat). Figure 2 shows the Aral Sea in 2014, with the gray line showing the former extent of the lake. (Micklin 2007, Wikipedia 2018a, NASA 2014)

The demise of these lakes has not been caused primarily by a decline in precipitation, but rather by diversion of water for human consumption. In some cases, the consumption has been to provide potable water for large population, as in the case with Owens Lake and Los Angeles. In other cases, it has been to provide irrigation water for crops, as in the case with the Aral Sea.

Many aquatic species live in saline lakes, and the lake’s demise obviously devastates them. In addition, the survival of many species of migratory birds depends on an unbroken chain of places they can stop and refuel on their long journeys. Break the chain in even one place, and their survival is threatened. Saline lakes are one of the places birds stop during migration, and draining the lakes threatens to break the chain.

In addition, when saline lakes are emptied, what remains behind is a fine, salty dust that is laced with heavy metals and pesticide residue that drained into the lake over many years. It is picked up by the wind and blown for miles. Posts in this blog have discussed the health threats represented by airborne particulates, and the damage done by this salty dust has been well documented around the Aral Sea. Aerial photographs revealed salt plumes extending as much as 500 km. (310 miles) from the lake. It is considered an essential factor in the region’s high incidence of both acute and chronic illness. (Micklin 2007)

Of these lakes, the 2 with the highest percentage of remaining water are the Dead Sea and the Great Salt Lake. Wurtsburgh et al conclude that the key to conserving these lakes is to provide the river inflow needed to restore and sustain them. Otherwise, these once important lakes will remain (become) nothing but a choking dust in the wind.

Sources:

Micklin, Philip. 2007. The Aral Sea Disaster. Annual Review of Earth and Planetary Sciences. 35:47-72. Available online at http://www.annualreviews.org/action/doSearch?SeriesKey=earth&AllField=Micklin&startPage=&ContribAuthorStored=Micklin%2C%20Philip.NASA. 2014.

NASA. 2014. ”The Aral Sea Loses Its Eastern Lobe.” Earth Observatory. Downloaded 2018-01-04 from https://earthobservatory.nasa.gov/IOTD/view.php?id=84437.

Wikipedia. 2018a. “Aral Sea.” Wikipedia. Viewed online 2018-01-04 at https://en.wikipedia.org/wiki/Aral_Sea.

Wikipedia. 2018b. “Dead Sea.” Wikipedia. Viewed online 2018-01-04 at https://en.wikipedia.org/wiki/Dead_Sea.

Wikiepedia. 2018c. “Owens Lake.” Wikipedia. Viewed online 2018-01-04 at https://en.wikipedia.org/wiki/Owens_Lake.

Wurtsbaugh, Wayne, Craig Miller, Sarah Null, Justin DeRose, Peter Wilcock, Maura Hahnenberger, Frank Howe, and Johnnie Moore. 2017. Nature Geoscience, Vol 10. DOI: 10.1038/NGEO3052. Available online at www.nature.com/naturegeoscience.

Good Days Are Better in Bryce Canyon, and Bad Days Are, Too

Figure 1. Air Pollution Affects Visibility at Bryce Canyon National Park. Source: National Park Service, 2017.

I began my last post with photographs taken in Bryce Canyon National Park on three days ranging from clear to hazy, shown again at right. Because it is one of the most remote locations in the continental USA, it is a good place to observe background air pollution.

(Click on photo for larger view.)

The haze in Bryce Canyon is caused by pollutants that have dispersed widely throughout the atmosphere. The previous post reviewed data on two pollutants that contribute the most to acid rain: sulfur dioxide and nitrogen dioxide.

Bryce Canyon, however, is most impacted by particulates, tiny particles that float freely in the air. They are too small to be seen individually with the naked eye, but collectively they cause haze. They also get into your lungs when you breathe, where they cause lung disease and other problems. The smallest ones (PM2.5) get most deeply into your lungs and are the greatest health hazard. How small are they? They are 2.5 microns or less in diameter, while the average human hair is 50-70 microns in diameter.

Figure 2. Source: IMPROVE Aerosol RHR (New Equation) Dataset.

I downloaded PM2.5 data from the Bryce Canyon IMPROVE Site. For each year, I selected the 10 highest readings and I averaged them. Then I selected the 10 lowest readings and I averaged them. The results are shown in the graph at right. The blue line represents the high readings, the red line the low readings.

Since 1983 the level of particulates on good days has trended slightly down.

In 1983 the bad days had roughly 5 times as much particulate matter in the air as the good days. The level of particulates on bad days trended up and peaked in 2009, about 20 years after data collection started. By then, the level had almost doubled, and the level of particulate matter on bad days was approximately 20 times the level on low days. Since then, the PM2.5 level has declined, and is now slightly lower than the level at which it started.

I don’t know what accounts for the reversal. My first guess would be the retirement of one or more coal-burning power plants, but searching the web does not seem to indicate it. The Navajo Generating Station, the largest in the West and the closest to Bryce Canyon, has been scheduled for retirement, but it has not occurred yet. It has been required to upgrade its pollution control equipment over the years, and perhaps that plays a role. It is also possible, however, that pollution from as far away as Las Vegas, Phoenix, or Southern California may have been involved. I just don’t know. If somebody out there does, please leave a comment and let us all know.

It was an issue of concern that the PM2.5 level on bad days continued to trend upward for so many years, and, whatever the cause, it is a relief to see that it has declined significantly. Hopefully it will decline even further from here.

Sources:

IMPROVE Aerosol RHR (New Equation) Dataset, Database Query Wizard, Federal Land Manager Database, Interagency Monitoring of Protected Visual Environments (IMPROVE). http://views.cira.colostate.edu/web/DataWizard.

Source: Federal Land Manager Environmental Database. Database Query Wizard. Data downloaded 12/8/2017 from http://views.cira.colostate.edu/fed/DataWizard/Default.aspx.

Background Air Quality 2017

Several times this blog has reported on air pollution, especially focusing on the Air Quality Index published by the EPA. In general, air quality has improved significantly. (The most recent series starts here.) The Air Quality Index monitoring program in Missouri focuses on large metropolitan areas or potentially large sources of pollution. Monitoring sites are often located next to pollution sources such as busy highways, industrial areas, or smelters. The sites monitor pollution where it is most likely to be most intense, but they don’t tell us much about the background level of pollution that has dispersed into the atmosphere.

Air Pollution Affects Visibility at Bryce Canyon National Park. Source: National Park Service, 2017.

The photos at right show Bryce Canyon National Park on three days ranging from clear to hazy. Bryce Canyon is dry, so the haze is not caused by humidity, it is air pollution. But Bryce Canyon is one of the remotest locations in the continental United States. It is close to no cities and no major sources of air pollution. The haze is caused by pollution that has dispersed widely into the atmosphere.

Spurred by the problem of acid rain, in 1990 the Environmental Protection Agency, National Park Service, and Bureau of Land Management established a network of rural monitoring sites far from cities and significant sources of pollution, called the Clean Air Status and Trends Network (CASTNET). These cites monitor the degree to which pollutants have dispersed into the ambient air. CASTNET has grown into a national network of 95 monitoring sites. CASTNET focuses on only a few pollutants most relevant for acid rain: sulfur dioxide and sulfates, nitric acid and nitrates, and ozone. (Clean Air Status and Trends Network 2017a)

No CASTNET monitoring sites are located in Missouri. Sites are located in Clark County Arkansas, Champaign, DuPage, Jo Daviess, and Madison Counties in Illinois, Brown and Riley Counties in Kansas, and Adair County in Oklahoma. (Clean Air Status and Trends Network 2017b)

The program to reduce the air pollution that causes acid rain has been one of the most successful environmental programs in our nation’s history. Two of the principal causes of acid rain are sulfur dioxide and nitrogen dioxide. When these gases are emitted by power plants and vehicles, they mix with water vapor already present in the air to form sulfuric acid and nitric acid. Even in this diluted form, these powerful acids fall with the rain, killing plants and dissolving metal, stonework, and concrete. Forests are affected, of course, but in addition, billions of dollars of damage has been done to buildings, bridges and roads.

Figures 1-4 map the average background concentration of sulfur dioxide over 4 periods: 1989-1991, 1999-2001, 2009-2011, and 2011-2014. Figures 5-8 map the average background concentration of nitric acid over the same 4 periods. (Be sure to notice that there is a decade between the first three maps in each series, but fewer years between the final two.)

Suflfur Dioxide Maps

Figure 1. Source: CASTNET 2017a.

Figure 2. Source: CASTNET 2017a.

 

 

 

 

 

 

 

 

Figure 3. Source: CASTNET 2017a.

Figure 4. Source: CASTNET 2017a.

 

 

 

 

 

 

 

 

 

 

Nitric Acid Maps

Figure 5. Source: CASTNET 2017a.

Figure 6. Source: CASTNET 2017a.

 

 

 

 

 

 

 

 

Figure 7. Source: CASTNET 2017a.

Figure 8. Source: CASTNET 2017a.

 

 

 

 

 

 

 

 

 

 

First, notice that the white space on the maps disappears over time. The CASTNET system did not cover the whole country at first, and this represents the development of the system.

Second, notice that in 1989-1991, the area of high pollution concentration extended from roughly Missouri to the eastern and northeastern portions of the country. The prevailing wind blows west-to-east, blowing pollution from the Midwest to the East.

Third, notice that over time the areas of red and orange have disappeared, and the area of yellow has been much reduced. The background atmospheric concentration of these two pollutants is much less than it was in 1989.

The background level of sulfur dioxide has improved significantly in Missouri and across the entire eastern portion of the country. Across the West, it does not appear to have been very high when measurements started. On the other hand, across the West the high background concentration of nitric acid appears to have occurred primarily in Southern California. It has improved. So has the background concentration of nitric acid across Missouri and the entire eastern portion of the country.

Sources

Clean Air Status and Trends Network. 2017a. Ambient Air Concentrations. Downloaded 12/1/2017 from https://www3.epa.gov/castnet/maps/airconc.html.

Clean Air Status and Trends Network. 2017b. Clean Air Status and Trends Network (CASTNET): Program Overview. https://www3.epa.gov/castnet/docs/CASTNET-Factsheet-2015.pdf.

Clean Air Status and Trends Network. 2017c. Site Information, Clean Air Status and Trends Network, EPA, http://java.epa.gov/castnet/epa_jsp/sites.jsp.

National Park Service. 2017. Air Pollution Impacts, Bryce Canyon National Park. Downloaded 12/2/2017 from https://www.nature.nps.gov/air/Permits/aris/brca/impacts.cfm?tab=0#TabbedPanels1.

Happy Holidays

I’m going on break until January 4. There will be data on background air pollution and on average world temperatures to look at when I resume posting. In the mean time:

.

It has been a dark year for America and for the world.
 
Remember that in the midst
of even the blackest night
the sun creeps toward the horizon
bringing light and hope
with the new day.
 
So in December
just as the coldest weather sets in
the seasons change
and the sun begins to move
towards spring
when it will bring
warmth and new life
to a grateful world.
 
May your holidays be warm
and full of good cheer
.
(Photo by John May)

Worldwide Carbon Dioxide Emissions Holding Constant

A recent article in the New York Times by Eduardo Porter (here) points out that if one considers only carbon dioxide emissions (CO2) from the combustion of fuels, then worldwide emissions have been flat for 3 years in a row.

Figure 1. Source: International Energy Agency, 2017b.

The finding comes from a news release issued by the International Energy Agency (IEA). Figure 1 shows the data. Between 1980 and 2014, global CO2 emissions from fuel combustion grew from 17.7 billion metric tons to 32.3 billion metric tons. However, in 2015 they stayed at 32.3 billion metric tons, and in 2016 emissions were 32.1 billion metric tons. (IEA 2017a, 2017b)

Since 2005, CO2 emissions from fuel combustion have declined in the OECD from 12.8 billion metric tons to 11.7 billion metric tons, a decline of 8.6%. In the United States, emissions declined from 6.71 billion metric tons to 5.00 metric tons (a decline of 25%). That’s good work, however it needs to be put in context. Compared to 1990, OECD emissions in 2016 were 6.4% higher, and USA emissions were 4.1% higher. (IEA 2017a)

I don’t have breakouts by country for 2016, but in 2015 the world’s largest emitter of CO2 from fuel combustion was the People’s Republic of China (mainland China), at 7.28 billion metric tons. Even China is reducing its emissions, however, by 1% in both 2015 and 2016. (IEA 2017a)

Emissions from fuel combustion may be the best estimate of worldwide emissions available. They constitute the largest percentage of emissions, and it is virtually impossible to inventory how much methane is being released by every bog or permafrost around the world, or how much nitrogen oxide from farm chemicals, etc.

Figure 2. Source: Earth Systems Research Laboratory, 2017.

In August I posted that the American Meteorological Society reported that in 2015 the concentration of CO2 in the atmosphere averaged above 400 ppm for the first time ever. It was my opinion that this was terrible news: 400 ppm was something akin to a threshold we needed not to cross in order to avoid the worst effects of climate change. We crossed it decades before anybody thought we would. Further, the concentration of greenhouse gases was continuing to increase, and the rate of increase seemed, if anything, to be growing over time. Figure 2 repeats the chart showing the trend over time.

How can one reconcile that post with the new findings? Imagine you are on the Titanic, and an hour ago the ship struck an iceberg. The ship’s crew happily reports that the amount of water getting into the ship is no longer increasing minute-by-minute. Well, that’s nice to hear, but water is still pouring into the ship, and unless you can stop the water getting in, the ship will still sink. The CO2 situation is similar, but in reverse. The rate at which the world is putting CO2 into the atmosphere may not be going up, but we are still putting billions of tons of it into the atmosphere every year. It is more than enough to cause climate change. We don’t need emissions to flatten, we need them to decrease to a fraction of what they are today.

So, it is good news that worldwide emissions have not grown over the last 3 years. Perhaps it even tends to validate the efforts we’ve been making: maybe moving away from fossil fuels, especially coal, has helped stabilize emissions. But we have a long way to go before we stop this vessel of ours from sinking.

UPDATE: The Global Carbon Project released a report published 11/13/2017 (after this post was written) that projects 2017 carbon emissions from combustion of fuels will increase 2% from 2016. If their estimates prove correct, then the period of flat emissions will be over, and emissions will have resumed their upward climb. (Global Carbon Project, 2017)

Sources:

Earth System Research Laboratory. 2017. Full Mauna Loa CO2 Record. Downloaded 2017-06-15 from https://www.esrl.noaa.gov/gmd/ccgg/trends.

Global Carbon Project. 2017. Global Carbon Budget: Summary Highlights. Viewed online 11/15/2017 at http://www.globalcarbonproject.org/carbonbudget/17/highlights.htm.

International Energy Agency. 2017a. CO2 Emissions from Fuel Combustion: Highlights. Downloaded 11/09/2017 from https://www.iea.org/publications/freepublications/publication/CO2EmissionsfromFuelCombustionHighlights2017.pdf

International Energy Agency. 2017b. IEA Finds CO2 Emissions Flat for Third Straight Year Even as Global Economy Grew in 2016. Downloaded 2017-11-09 from https://www.iea.org/newsroom/news/2017/march/iea-finds-co2-emissions-flat-for-third-straight-year-even-as-global-economy-grew.html.